Question

For the gas phase decomposition of chloroethane,

CH3CH2Cl C2H4 + HCl

the rate constant at 723 K is 1.75E-4 /s and the rate constant at 769 K is 2.19E-3 /s.

The activation energy for the gas phase decomposition of chloroethane is

Answer 1

USe the combined arrehiuns equation and solve for Ea:

ln(k1/k2 )=Ea/R(1/T2−1/T1)

Where

k1=1.75 x 10^-4
T1=723K
k2=2.19 x 10^-3
T2=769K
R= 8.314 J/mol*K
And
Ea=?

ln(1.75 x 10^-4/2.19 x 10^-3 )=Ea/8.314 J/mol*K(1/769K−1/723K)

-2.5269=Ea/8.314 J/mol*K(-8.2736 x 10^-5)

-2.5269/-8.2736 x 10^-5=Ea/8.314 J/mol*K

3.054 x 10^4=Ea/8.314 J/mol*K

Ea=3.054 x 10^4*8.314 J/mol*K

Ea=2.54 x 10^5 J/mol